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MSphere Jul 2019Outbreaks of the emerging arbovirus chikungunya virus (CHIKV) affect millions of individuals in Asia, Africa, and Latin America. Vector competence can be changed...
Outbreaks of the emerging arbovirus chikungunya virus (CHIKV) affect millions of individuals in Asia, Africa, and Latin America. Vector competence can be changed dramatically by single amino acid exchanges located predominantly within the CHIKV E1 and E2 envelope proteins, which are associated with enhanced transmissibility by anthropophilic mosquitoes. Commonly used reference assays for molecular surveillance cover only a few adaptive mutations within the envelope domains and have not been validated for all CHIKV genotypes. The recognized landscape of CHIKV adaptive mutations is thus likely incomplete. We designed two nested reverse transcription-PCR (RT-PCR) assays that cover hot spots of viral adaptation to vectors within the E1 and E2 genomic domains. Primers were designed in conserved genomic regions to allow broad usability across CHIKV genotypes. The sensitivity of both assays was at least equivalent to E1- and E2-based reference assays and robust among CHIKV genotypes at 51.4 IU/reaction (E1, 95% confidence interval [CI], 39.8 to 78.9) and 4.0 IU/reaction (E2, 95% CI, 2.0 to 7.4). Upon analysis of the complete known CHIKV genomic diversity, up to 11 nucleotide mismatches with CHIKV variants occurred under oligonucleotide binding sites of reference assays, potentially limiting assay sensitivity, whereas no critical mismatches occurred in the new assays. Specificity testing with nine alphaviruses representing all serocomplexes showed amplification of Mayaro virus and O'nyong-nyong virus by the E1-based assay, but not by the E2-based assay. The high sensitivity and specificity of the new E2-based assay may allow its diagnostic usage in resource-limited settings. The combined new assays allow improved molecular epidemiological surveillance of CHIKV globally. The life cycle of arboviruses relies on efficient infection of and transmission by arthropod vectors. Adaptation to new vectors can thus dramatically increase the geographic range of an arbovirus. Several adaptive mutations enhance chikungunya virus (CHIKV) transmissibility by different mosquito species. The appearance of those adaptive mutations has led to large-scale CHIKV outbreaks in Asia, Africa, and Europe. Molecular surveillance of circulating CHIKV strains for adaptive mutations contributes to precise risk assessments and efficient vector control and provides new insight into the evolution of vector adaptation. Existing assays for molecular CHIKV surveillance are limited by poor coverage of known adaptive mutations, low sensitivity, and cost-intensive deep sequencing approaches, preventing universal application. We developed two highly sensitive nested RT-PCR assays that cover hot spots of vector adaptation in CHIKV envelope domains. The new assays allow unprecedented molecular surveillance across all CHIKV genotypes and diagnostic use in resource-limited settings globally.
Topics: Adaptation, Physiological; Animals; Chikungunya Fever; Chikungunya virus; DNA Primers; Genome, Viral; Genotype; Molecular Epidemiology; Mosquito Vectors; Mutation; Polymerase Chain Reaction; RNA, Viral; Viral Envelope Proteins
PubMed: 31270168
DOI: 10.1128/mSphere.00295-19 -
Current Issues in Molecular Biology 2021sensu lato causes Lyme borreliosis in a variety of animals and humans. These atypical bacterial pathogens are maintained in a complex enzootic life cycle that primarily...
sensu lato causes Lyme borreliosis in a variety of animals and humans. These atypical bacterial pathogens are maintained in a complex enzootic life cycle that primarily involves a vertebrate host and spp. ticks. In the Northeastern United States, is the main vector, while wild rodents serve as the mammalian reservoir host. As is transmitted only by and closely related ticks, the spirochete-tick interactions are thought to be highly specific. Various borrelial and arthropod proteins that directly or indirectly contribute to the natural cycle of infection have been identified. Discrete molecular interactions between spirochetes and tick components also have been discovered, which often play critical roles in pathogen persistence and transmission by the arthropod vector. This review will focus on the past discoveries and future challenges that are relevant to our understanding of the molecular interactions between and ticks. This information will not only impact scientific advancements in the research of tick- transmitted infections but will also contribute to the development of novel preventive measures that interfere with the life cycle.
Topics: Animals; Arachnid Vectors; Borrelia burgdorferi; Host-Pathogen Interactions; Humans; Ixodes; Life Cycle Stages; Lyme Disease; Northwestern United States; Ticks
PubMed: 33289683
DOI: 10.21775/cimb.042.113 -
PLoS Computational Biology Dec 2021Many plant viruses are transmitted by insect vectors. Transmission can be described as persistent or non-persistent depending on rates of acquisition, retention, and...
Many plant viruses are transmitted by insect vectors. Transmission can be described as persistent or non-persistent depending on rates of acquisition, retention, and inoculation of virus. Much experimental evidence has accumulated indicating vectors can prefer to settle and/or feed on infected versus noninfected host plants. For persistent transmission, vector preference can also be conditional, depending on the vector's own infection status. Since viruses can alter host plant quality as a resource for feeding, infection potentially also affects vector population dynamics. Here we use mathematical modelling to develop a theoretical framework addressing the effects of vector preferences for landing, settling and feeding-as well as potential effects of infection on vector population density-on plant virus epidemics. We explore the consequences of preferences that depend on the host (infected or healthy) and vector (viruliferous or nonviruliferous) phenotypes, and how this is affected by the form of transmission, persistent or non-persistent. We show how different components of vector preference have characteristic effects on both the basic reproduction number and the final incidence of disease. We also show how vector preference can induce bistability, in which the virus is able to persist even when it cannot invade from very low densities. Feedbacks between plant infection status, vector population dynamics and virus transmission potentially lead to very complex dynamics, including sustained oscillations. Our work is supported by an interactive interface https://plantdiseasevectorpreference.herokuapp.com/. Our model reiterates the importance of coupling virus infection to vector behaviour, life history and population dynamics to fully understand plant virus epidemics.
Topics: Animals; Computational Biology; Genetic Fitness; Host-Pathogen Interactions; Insect Vectors; Models, Biological; Plant Diseases; Plant Viruses
PubMed: 34968387
DOI: 10.1371/journal.pcbi.1009759 -
Current Opinion in Insect Science Aug 2019The proven ability of vector mosquitoes to adapt to various strategies developed to control them has enabled mosquito-borne diseases such as malaria, dengue, and... (Review)
Review
The proven ability of vector mosquitoes to adapt to various strategies developed to control them has enabled mosquito-borne diseases such as malaria, dengue, and lymphatic filariasis to remain entrenched as public health threats all over the world. Rather than continuing to seek a miracle cure for all mosquito vector problems among the ranks of single mode-of-action chemical pesticides, today's developers of vector control strategies are increasingly turning to more integrated, varied techniques, relying on pheromones and other semiochemicals to effect vector control through behavioral manipulation of the vector. Examples of this focus include attract-and-kill technologies utilizing floral odors and vertebrate host-associated scent cues to achieve control of adult mosquitoes, and selective oviposition attractants and larval phagostimulants to improve the efficacy of bacterial larvicides.
Topics: Animals; Mosquito Control; Mosquito Vectors; Odorants
PubMed: 31247410
DOI: 10.1016/j.cois.2019.05.007 -
Pathogens and Disease Apr 2021Bacterial infection is a highly complex biological process involving a dynamic interaction between the invading microorganism and the host. Specifically, intracellular... (Review)
Review
Bacterial infection is a highly complex biological process involving a dynamic interaction between the invading microorganism and the host. Specifically, intracellular pathogens seize control over the host cellular processes including membrane dynamics, actin cytoskeleton, phosphoinositide metabolism, intracellular trafficking and immune defense mechanisms to promote their host colonization. To accomplish such challenging tasks, virulent bacteria deploy unique species-specific secreted effectors to evade and/or subvert cellular defense surveillance mechanisms to establish a replication niche. However, despite superficially similar infection strategies, diverse Rickettsia species utilize different effector repertoires to promote host colonization. This review will discuss our current understandings on how different Rickettsia species deploy their effector arsenal to manipulate host cellular processes to promote their intracytosolic life within the mammalian host.
Topics: Actin Cytoskeleton; Animals; Arthropod Vectors; Host Specificity; Host-Pathogen Interactions; Humans; Metabolic Networks and Pathways; Mites; Phosphatidylinositols; Phthiraptera; Phylogeny; Rickettsia; Rickettsia Infections; Siphonaptera; Species Specificity; Ticks
PubMed: 33705517
DOI: 10.1093/femspd/ftab015 -
Nature Communications Jul 2021Mosquito-borne diseases, such as dengue and malaria, pose significant global health burdens. Unfortunately, current control methods based on insecticides and... (Review)
Review
Mosquito-borne diseases, such as dengue and malaria, pose significant global health burdens. Unfortunately, current control methods based on insecticides and environmental maintenance have fallen short of eliminating the disease burden. Scalable, deployable, genetic-based solutions are sought to reduce the transmission risk of these diseases. Pathogen-blocking Wolbachia bacteria, or genome engineering-based mosquito control strategies including gene drives have been developed to address these problems, both requiring the release of modified mosquitoes into the environment. Here, we review the latest developments, notable similarities, and critical distinctions between these promising technologies and discuss their future applications for mosquito-borne disease control.
Topics: Animals; Animals, Genetically Modified; CRISPR-Cas Systems; Female; Humans; Insecticides; Malaria; Male; Mosquito Control; Mosquito Vectors; Nucleic Acid Amplification Techniques; Pest Control, Biological; Vector Borne Diseases; Wolbachia
PubMed: 34282149
DOI: 10.1038/s41467-021-24654-z -
Viruses Jan 2020The risk of emergence and/or re-emergence of arthropod-borne viral (arboviral) infections is rapidly growing worldwide, particularly in Africa. The burden of arboviral... (Review)
Review
The risk of emergence and/or re-emergence of arthropod-borne viral (arboviral) infections is rapidly growing worldwide, particularly in Africa. The burden of arboviral infections and diseases is not well scrutinized because of the inefficient surveillance systems in endemic countries. Furthermore, the health systems are fully occupied by the burden of other co-existing febrile illnesses, especially malaria. In this review we summarize the epidemiology and risk factors associated with the major human arboviral diseases and highlight the gap in knowledge, research, and control in Sudan. Published data in English up to March 2019 were reviewed and are discussed to identify the risks and challenges for the control of arboviruses in the country. In addition, the lack of suitable diagnostic tools such as viral genome sequencing, and the urgent need for establishing a genomic database of the circulating viruses and potential sources of entry are discussed. Moreover, the research and healthcare gaps and global health threats are analyzed, and suggestions for developing strategic health policy for the prevention and control of arboviruses with focus on building the local diagnostic and research capacity and establishing an early warning surveillance system for the early detection and containment of arboviral epidemics are offered.
Topics: Animals; Arbovirus Infections; Arboviruses; Arthropod Vectors; Biomedical Research; Communicable Disease Control; Epidemics; Genome, Viral; Humans; Risk Factors; Sudan
PubMed: 31936607
DOI: 10.3390/v12010081 -
Vector Borne and Zoonotic Diseases... Feb 2020Two species of mosquitoes ( and ) are primary vectors for emerging arboviruses that are a significant threat to public health and economic burden worldwide.... (Review)
Review
Two species of mosquitoes ( and ) are primary vectors for emerging arboviruses that are a significant threat to public health and economic burden worldwide. Distribution of these vectors and the associated arboviruses, such as dengue virus, chikungunya virus, yellow fever virus, and Zika virus, was for a long time restricted by geographical, ecological, and biological factors. Presently, arbovirus emergence and dispersion are more rapid and geographically widespread, largely due to expansion of the range for these two mosquitoes that have exploited the global transportation network, land perturbation, and failure to contain the mosquito population coupled with enhanced vector competence. and may also sustain transmission between humans without having to depend on their natural reservoir forest cycles due to arthropod adaptation to urbanization. Currently, there is no single strategy that is adequate to control these vectors, especially when managing arbovirus outbreaks. This review aimed at presenting the characteristics and abilities of and , which can drive a global public health risk, and suggests strategies for prevention and control. This review presents the geographic range, reproduction and ecology, vector competence, genetic evolution, and biological and chemical control of these two mosquito species and how they have changed and developed over time combined with factors that may drive pandemics and mitigation measures. We suggest that more efforts should be geared toward the development of a concerted multidisciplinary approach.
Topics: Aedes; Animal Distribution; Animals; Arbovirus Infections; Arboviruses; Humans; Mosquito Control; Mosquito Vectors; Pandemics; Risk Factors
PubMed: 31556813
DOI: 10.1089/vbz.2019.2486 -
Journal of Medical Entomology Mar 2022Aedes albopictus (Skuse) and Aedes aegypti (Linnaeus) (Diptera: Culicidae) mosquitoes transmit pathogenic arthropod-borne viruses, including dengue, chikungunya, and...
Aedes albopictus (Skuse) and Aedes aegypti (Linnaeus) (Diptera: Culicidae) mosquitoes transmit pathogenic arthropod-borne viruses, including dengue, chikungunya, and Zika viruses, with significant global health consequences. Both Ae. albopictus and Ae. aegypti also are susceptible to Aedes flavivirus (AEFV), an insect-specific flavivirus (ISF) first isolated in Japan from Ae. albopictus and Ae. flavopictus. ISFs infect only insect hosts and evidence suggests that they are maintained by vertical transmission. In some cases, ISFs interfere with pathogenic flavivirus infection, and may have potential use in disease control. We explored the host range of AEFV in 4 genera of mosquitoes after intrathoracic injection and observed greater than 95% prevalence in the species of Aedes and Toxorhynchites tested. Anopheles and Culex species were less permissive to infection. Vertical transmission studies revealed 100% transovarial transmission and a filial infection rate of 100% for AEFV in a persistently-infected colony of Ae. albopictus. Horizontal transmission potential was assessed for adult and larval mosquitoes following per os exposures and in venereal transmission experiments. No mosquitoes tested positive for AEFV infection after blood feeding, and infection with AEFV after sucrose feeding was rare. Similarly, 2% of adult mosquitoes tested positive for AEFV after feeding on infected cells in culture as larvae. Venereal transmission of AEFV was most frequently observed from infected males to uninfected females as compared with transmission from infected females to uninfected males. These results reveal new information on the infection potential of AEFV in mosquitoes and expand our understanding of both vertical and horizontal transmission of ISFs.
Topics: Aedes; Animals; Biology; Female; Flavivirus; Insecta; Larva; Male; Mosquito Vectors; Zika Virus; Zika Virus Infection
PubMed: 35064663
DOI: 10.1093/jme/tjab197 -
Annual Review of Genetics Dec 2019is an endosymbiotic that can suppress insect-borne diseases through decreasing host virus transmission (population replacement) or through decreasing host population... (Review)
Review
is an endosymbiotic that can suppress insect-borne diseases through decreasing host virus transmission (population replacement) or through decreasing host population density (population suppression). We contrast natural infections in insect populations with transinfections in mosquitoes to gain insights into factors potentially affecting the long-term success of releases. Natural infections can spread rapidly, whereas the slow spread of transinfections is governed by deleterious effects on host fitness and demographic factors. Cytoplasmic incompatibility (CI) generated by is central to both population replacement and suppression programs, but CI in nature can be variable and evolve, as can fitness effects and virus blocking. spread is also influenced by environmental factors that decrease titer and reduce maternal transmission frequency. More information is needed on the interactions between and host nuclear/mitochondrial genomes, the interaction between invasion success and local ecological factors, and the long-term stability of -mediated virus blocking.
Topics: Animals; Biological Evolution; Communicable Disease Control; Cytoplasm; Environment; Genetic Fitness; Host-Pathogen Interactions; Insect Vectors; Insecta; Mosquito Vectors; Wolbachia
PubMed: 31505135
DOI: 10.1146/annurev-genet-112618-043609